From: Jason Gunthorpe <jgg@ziepe.ca>
To: Baolu Lu <baolu.lu@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Nicolin Chen <nicolinc@nvidia.com>, Yi Liu <yi.l.liu@intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Joel Granados <j.granados@samsung.com>,
iommu@lists.linux.dev, virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/9] iommu: Replace sva_iommu with iommu_attach_handle
Date: Mon, 29 Apr 2024 17:24:58 -0300 [thread overview]
Message-ID: <20240429202458.GR231144@ziepe.ca> (raw)
In-Reply-To: <5871aaec-b81a-4ad4-8eb1-656a04d04bda@linux.intel.com>
On Sun, Apr 28, 2024 at 06:22:28PM +0800, Baolu Lu wrote:
> /* A bond already exists, just take a reference`. */
> handle = iommu_attach_handle_get(group, iommu_mm->pasid);
> if (handle) {
> if (handle->domain->iopf_handler != iommu_sva_iopf_handler)
> {
> ret = -EBUSY;
> goto out_unlock;
> }
>
> refcount_inc(&handle->users);
> mutex_unlock(&iommu_sva_lock);
> return handle;
> }
>
> But it appears that this code is not lock safe. If the domain on the
> PASID is not a SVA domain, the check of "handle->domain->iopf_handler !=
> iommu_sva_iopf_handler" could result in a use-after-free issue as the
> other thread might detach the domain in between the fetch and check
> lines.
For the above you just need to pass in the iommu_sva_iopf_handler as
an argument to attach_handle_get() and have it check it under the
xa_lock.
The whole thing is already protected under the ugly sva_lock.
Ideally it would be protected by the group mutex..
Jason
next prev parent reply other threads:[~2024-04-29 20:25 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-03 1:15 [PATCH v4 0/9] IOMMUFD: Deliver IO page faults to user space Lu Baolu
2024-04-03 1:15 ` [PATCH v4 1/9] iommu: Introduce domain attachment handle Lu Baolu
2024-04-03 11:58 ` Jason Gunthorpe
2024-04-06 4:34 ` Baolu Lu
2024-04-08 14:05 ` Jason Gunthorpe
2024-04-09 1:34 ` Baolu Lu
2024-04-09 1:53 ` Baolu Lu
2024-04-09 23:37 ` Jason Gunthorpe
2024-04-10 0:25 ` Tian, Kevin
2024-04-03 1:15 ` [PATCH v4 2/9] iommu: Replace sva_iommu with iommu_attach_handle Lu Baolu
2024-04-03 11:59 ` Jason Gunthorpe
2024-04-06 6:09 ` Baolu Lu
2024-04-08 14:19 ` Jason Gunthorpe
2024-04-09 2:11 ` Baolu Lu
2024-04-09 23:48 ` Jason Gunthorpe
2024-04-10 6:12 ` Baolu Lu
2024-04-28 10:22 ` Baolu Lu
2024-04-29 2:39 ` Tian, Kevin
2024-04-29 5:07 ` Baolu Lu
2024-04-29 20:24 ` Jason Gunthorpe [this message]
2024-04-06 6:28 ` Baolu Lu
2024-04-03 1:15 ` [PATCH v4 3/9] iommu: Add attachment handle to struct iopf_group Lu Baolu
2024-04-03 1:15 ` [PATCH v4 4/9] iommufd: Fault-capable hw page table attach/detach/replace Lu Baolu
2024-04-03 1:15 ` [PATCH v4 5/9] iommufd: Add fault and response message definitions Lu Baolu
2024-04-03 1:15 ` [PATCH v4 6/9] iommufd: Add iommufd fault object Lu Baolu
2024-04-03 1:15 ` [PATCH v4 7/9] iommufd: Associate fault object with iommufd_hw_pgtable Lu Baolu
2024-04-03 1:15 ` [PATCH v4 8/9] iommufd/selftest: Add IOPF support for mock device Lu Baolu
2024-04-03 1:15 ` [PATCH v4 9/9] iommufd/selftest: Add coverage for IOPF test Lu Baolu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240429202458.GR231144@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=baolu.lu@linux.intel.com \
--cc=iommu@lists.linux.dev \
--cc=j.granados@samsung.com \
--cc=jacob.jun.pan@linux.intel.com \
--cc=jean-philippe@linaro.org \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=nicolinc@nvidia.com \
--cc=robin.murphy@arm.com \
--cc=virtualization@lists.linux-foundation.org \
--cc=will@kernel.org \
--cc=yi.l.liu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).